Preheat oven to 425°F.

In a large bowl, combine sugar and flour. Sift in almond meal, breaking apart clumps in the sifter as needed. Sift in cocoa. Whisk until uniform. Set aside.

Place butter in a skillet over medium heat. When melted, whisk to keep milk solids suspended in the oil. Continue cooking and whisking until butter is a hazelnut brown, about 10 minutes. Strain, measuring 100g of browned butter, into a medium saucepan.

Add chocolate to browned butter and stir until melted and smooth. If needed, place back over medium heat to ensure chocolate is melted. Set aside.

Make a well in the center of the sugar mixture and add egg whites. Start whisking egg whites, slowly incorporating the sugar mixture. Continue until batter is thick and uniform. Scrape down sides and bottom of the bowl and re-whisk.

While whisking, slowly add hot butter-chocolate mixture. Continue whisking until uniform.

Transfer to a piping bag with a 3/8-inch tip or opening.

Pipe batter into mini-muffin tins, filling each to about 1/8-inch from the top.

Place in the oven and immediately lower temperature to 350°F. Bake 14-16 minutes, or until a skewer inserted into the center comes out clean.

Use a sharp knife to loosen financiers and remove to a rack to cool completely.